Pipes like the GYTR and LEXX dont Have to have a new mapper. The stock system will adjust to minor airflow changes with those pipes. (otherwise you could not ride at 10,000 feet and - 200 feet and not change your mapping on a stock quad) At least that is what they told me...I have had a LEXX pipe for two years with no air box lid and have had no issues. I check my plug every few rides and its always nice and brown.
You wont get as much horsepower but honestly who fricking rides wide open? I have gotten into fith gear wide open maybe 5 times racing this year and not once did I think "Wow I really wish I could go faster down this whooped out dirt road"....Unless it is gonna be a dune racer I would say your fine...Thats my 2 cents..I think every penny you want to put into your quad should be suspension...Like Wiigs Style Racing....Look for there banner on this site!